The present disclosure relates to image reading devices and image forming apparatuses, particularly relates to a technique of reading a light emitting display screen of a mobile information terminal and the like.
An image reading device such as a copier uses, for example, a light irradiation section to irradiate an original document, and reads an image from the original document by receiving the light reflected from the original document with a charge coupled device (CCD) sensor. In addition to a conventional paper medium, a display screen of a recently widely used mobile information terminal, such as smartphones and tablets, has become a reading target of the image reading device.
A smartphone and the like has a self-luminous display screen, thus in some cases, an electric charge of the CCD becomes saturated in reading the display screen, which causes the image reading device that reads reflected light to receive a light more than presumed volume. This results in a failure in reading the display screen with suitable gradation. A technique to reduce volume of a light source (light irradiation section) in a case where a reading target material has a light emitting screen is disclosed.
The display screen of the smartphone and the like sometimes displays a data code such as a QR code (a registered trademark). In a case where the smartphone displaying the QR code is a reading target of a copier, the copier outputs either a printed matter showing information embedded in the QR code or a printed matter showing the smartphone displaying the QR code.